There has been conventionally known an in-vehicle navigation device that acquires traffic information (VICS data) on traffic accidents and traffic jams etc. from a Vehicle Information Communication System (VICS) and superimposes indications representing the traffic condition such as the traffic accidents and the traffic jams on map information displayed on a screen of a display unit to notify users of the traffic condition.
As an example of such in-vehicle navigation device, there has been known an arrangement that predicts and notifies current and future traffic conditions with the use of statistical traffic-jam information data obtained by statistically processing the past traffic-jam information (see, for example, Patent Document 1).
An in-vehicle navigation device disclosed in Patent document 1 notifies statistical traffic-jam information according to time factors such as time and day of the week based on the statistical traffic-jam information data by superimposing the information on map information in various expressions corresponding to the traffic-jam condition. With the notified time and day of the week, users can predict current and possible future traffic jams.
As another example, there has been known an arrangement in which parking information is superimposed on map information to provide notification thereof (see, for instance, Nonpatent Document 1). The arrangement disclosed in Nonpatent Document 1 provides guidance such that, for instance, when a parking lot is full, it is indicated in red to show unavailability thereof, and when a parking lot has vacancy, it is indicated in blue to show availability thereof.
[Patent Document 1] Japanese Laid-Open Patent Publication No. Hei 9-113290 (right column of page 3 to left column of page 7).
[Nonpatent Document 1]
http://www.dvd-rakunavi.com/function/around/index.html (as of Jun. 11, 2004).